What Is a Fine Grained Igneous Rock?

Definition: Igneous rock in which the framework of the rock consists of crystals that are too small to determine mineralogy with the unaided eye; framework may include up to 50 percent glass. A significant percentage of the rock by volume may be phenocrysts

What is a fine grained igneous rock called?

Fine grained rocks are called "extrusive" and are generally produced through volcanic eruptions. ... Granite and gabbro are examples of phaneritic igneous rocks. Fine grained rocks, where the individual grains are too small to see, are called aphanitic. Basalt is an example.

What is fine grained rock?

i. Said of a crystalline rock, and of its texture, in which the individual minerals are relatively small; specif. said of an igneous rock whose particles have an average diameter less than 1 mm. Synonym of: aphanitic. Ref: AGI.